LVT(A)4 was based on LVT(A)1, but with a new turret mounting a 75mm howitzer. Both early and late armored cabs were fitted to LVT(A)4; machines with the ball-mounted MG in the cab and the .50cal MG were provided with 2000 rounds of .30cal ammunition. In later vehicles, the ring-mounted .50cal MG was replaced by a mount for a .30cal MG on either side of the rear of the turret. Late-production turrets had vision blocks installed in their rears and sides.

LVT(A)4 was fitted with a power traverse mechanism and elevation stabilizer and was then designated LVT(A)5. The stabilizer required mounting a counterweight on the howitzer barrel close to the gun shield. A second auxiliary generator was added to compensate for the increased demand for power. LVT(A)5 did not see service in the Second World War, and late in its life an armored cover was added to the turret.